1. Field of the invention
The present invention pertains to a control means incorporating a microprocessor for actuating a pump in accordance with programmable prescription parameters and dosage limits. The disclosed control means incorporates running integral dosage limits and other safety features which prevent an inadvertent or intentional medication overdose.
2. Description of the Comtemporary and/or Prior Art
Various techniques and devices have been suggested and are currently under study which addresses the problem of dispensing a drug or other medicative liquid into the living body. In these techniques and devices, however, redundant safety features and flexibility achieved by programming dosage inputs are rarely contemplated.
One liquid infusion device discussed in U. S. Pat. No. 4,007,405 by Haerten et al comprises a controlable dosing arrangement which provides for human operator interaction. A syringe forces liquid through a pressure valve into a supply reservoir and a bellows pump forces the drug from the reservoir through a flow limiter into the body. This device fails to address various safety problems such as leakage, excessive pumping, and excessive requests for drugs. No provision exists for detecting leaks in the device, for signalling malfunctions, for restricting the number of or quantity of drug doses, or for monitoring proper operation of the device.
Like Haerten et al, U. S. Pat. No. 3,692,027 by Ellinwood teaches an implanted, self-powered drug dispenser having a bellows pump which is fed through and expels the drug through valves, in particular one-way valves. The Ellinwood device is not programmable; it varies dosage by opening and closing portals or selecting a dose or medication from one of a plurality of pumps having different dosage volumes and/or different medications stored therein. Safety redundancy such as pressure integrity checks during filling, leakage problems, patient and doctor interaction with the dispenser, and dosage input programming are not considered.